The calculation shows the risk-neutral probability of an up move in a binomial tree model. Given:
- r = 12% annual interest rate
- Ξt = 3/12 = 0.25 years
- u = 1.2 (up factor)
- d = 0.8 (down factor)
The formula for risk-neutral probability is:
Pupβ=uβderΞtβdβ
Substituting the values:
Pupβ=1.2β0.8e0.12Γ0.25β0.8β=0.4e0.03β0.8β=0.41.03045β0.8β=0.40.23045β=0.576125β57.61%